The use of Late Jurassic bivalves (buchiids) in biostratigraphy has been successful in the northern circum-Pacific for a long time. In recent years the increase of detailed studies on other bivalve faunas has extended the potential biostratigraphic usefulness of bivalves to cover also the Early and Middle Jurassic of other circum-Pacific regions. Only some bivalve groups have proved useful, notably monotaceans and pectinaceans for the Lower Jurassic, inoceramids (s.l.) for the Middle Jurassic, and buchiids for the Upper Jurassic. As knowledge of systematics and vertical ranges of bivalve species is still very uneven, many more studies are needed to obtain a comprehensive picture. A correlation chart for several circum-Pacific regions has been compiled showing approximate equivalences (Table 16.1). This chart is mainly intended to stimulate further discussions on this subject.

As seen in Table 16.1, many of the biostratigraphic units recognized thus far are based on and named after local species belonging to mainly circum-Pacific genera, such as Otapiria, Radulonectites, Parainoceramus, Retroceramus (or Mytiloceramus), and Buchia. Although this is only a consequence of the fact that correlation tables are commonly based on offshore species, it makes comparison between circum-Pacific regions easier. This analysis should not overlook the progressive displacement of local vertical ranges of some of these bivalve taxa along their geographic ranges.